Comparative studies broaden our knowledge base, permitting the identification of suitable animal models for the study of complex hormone-regulated processes. In addition, by expanding our understanding of a larger sample of organisms, we are better able to recognize generalizations otherwise hidden by apparent disorder and thereby obtain insight into the human condition. A symposium entitled "Unconventional Vertebrates as Animal Models in Endocrine Research" is proposed. It has as its specific aims: 1) to highlight studies in comparative endocrinology which have significantly advanced our understanding of endocrine systems in general; 2) to identify the relatively untapped potential of vertebrates outside the range of common laboratory species for the study of current problems in endocrinology; 3) to assess the status of pre- and postdoctoral training in comparative endocrinology as a means of broadening the biological perspective of future researchers and as a resource for the development of new animal models in response to future needs; 4) to address problems associated with the acquisition, care, breeding and experimental use of unconventional laboratory species; 5) to initiate the establishment of a data bank for acquiring, cataloguing and retrieving basic and practical information about unconventional vertebrate species in order to promote and facilitate their use in the laboratory.